New York: Martha (Sunny) von Bulow, the American heiress who was first married to an Austrian playboy prince and then to a Danish-born man-about-society who was twice tried on charges of attempting to murder her, died Saturday at a nursing home in Manhattan. Von Bulow, who was 76, had been in a coma for nearly 28 years.

Family spokesperson Maureen Connelly confirmed the death. Von Bulow’s three children said in a statement that they “were blessed to have an extraordinary loving and caring mother".

Von Bulow’s death came 27 years, 11 months and 15 days after she was found unconscious on the floor of her bathroom in her mansion in Newport, Rhode Island, on 21 December 1980.

In her long, silent years at the Milstein Building at Columbia hospital and then at the nursing home on the Upper East Side, doctors said von Bulow never showed any signs of brain activity; she was fed through a tube in her stomach.

Yet there were always fresh flowers in her room, and photographs of her children and grandchildren sat on a bedside table. She was attended by private nurses, and her room, for some time, was guarded by private security personnel.

She is survived by her daughters, Annie-Laurie von Auersperg Kneissl Isham and Cosima Pavoncelli, her son, Alexander von Auersperg, and five grandchildren.

Her second husband, Claus von Bulow, was convicted and later acquitted of twice trying to kill her with injections of insulin so as to aggravate her low blood sugar condition.

His trials were among the most sensational of the 1980s. The news media from around the world were irresistibly drawn to the drama of the beautiful heiress who lay in a twilight zone, the debonair husband accused of murder, two royal children pitted against their younger stepsister and the glittering social milieus of Newport and New York providing the backdrop.

Hollywood, too, could not resist. The trials became the subject of the 1990 movie Reversal of Fortune with Glenn Close as Sunny von Bulow and Jeremy Irons as Claus von Bulow. The film was based on a book by Alan M. Dershowitz, the Harvard law professor who had been Claus von Bulow's lawyer during his appeal.

The prosecutions were the result of an investigation initiated at the time by Alexander von Auersperg and his sister Annie-Laurie von Auersperg Kneissl, the children of Sunny von Bulow’s marriage to Prince Alfred von Auersperg. The accusations pitted the von Auerspergs against their stepfather and their half-sister, Cosima von Bulow, and divided the loyalty of friends in both Newport and New York.

In his first trial, in Newport in 1982, Claus von Bulow was found guilty of twice trying to kill his wife and sentenced to 30 years in prison. He appealed and posted a $1 million (Rs4.97 crore) bond believed to have been put up by his friend J. Paul Getty Jr.

The appeal was guided by Dershowitz, working with a team of Harvard students, and the conviction was overturned on the grounds that certain information had not been made available to the defence and that there had been no search warrant when pills were confiscated and sent for testing.

Claus von Bulow was acquitted in 1985 after a second trial.

A $56 million civil suit filed against Claus von Bulow by his stepchildren was settled in 1987 with the stipulation that von Bulow agreed to a divorce and would not discuss the case publicly. The couple were divorced in 1988. Claus von Bulow lives in London.